This invention relates to semiconductor integrated circuit devices of multiple types, devices of each type being manufactured in a small number, and more particularly to a failure-ratio estimating method for estimating the failure-ratio of the devices of each type on the market and setting appropriate initial-failure screening conditions, and said method is employed when multiple types of semiconductor integrated circuit devices are developed and mass-produced. The invention also relates to a method for manufacturing the above-described semiconductor integrated devices, and to a semiconductor integrated circuit device for testing.
The process will be stated below, which is used for developing semiconductor integrated circuit devices (hereinafter referred to as "semiconductor devices") of multiple types, devices of each type being manufactured in a small number, such as ASICs (Application Specific ICs), and then mass-producing the developed devices.
First, the types of devices to be developed are determined. After determining the to-be-developed types of devices, it is determined what structure the testing semiconductor devices should have. After that, the degree of reliability demanded for transistors, aluminum wirings, contacts, etc. incorporated in a testing semiconductor device is determined. Then, the degree of reliability demanded for the entire testing semiconductor device is determined, which is the final step in the development process. Subsequently, integrated circuits are formed on a semiconductor wafer by performing treatments of thin film forming, exposure, etching, etc. Thereafter, an assembly process which includes the steps of dicing, bonding, packaging, etc. is performed to complete the testing semiconductor devices or testing products. The resultant testing products are analyzed to thereby estimate the reliability of the products and hence of semiconductor devices to be manufactured. The above-described steps are included in the development stage. Reliability estimation of semiconductor devices is performed as occasion demands in the development stage, and the estimation results are reflected in the mass production stage. The reliability estimation of semiconductor devices is based on the estimation of their failure ratio on the market.
Parallel to the development, mass production of products 1, 2, . . . , n is sequentially performed. In the manufacture of the products 1, mask forming, sample shipment and mass production are sequentially executed. The same can be said of the other products 2, 3, . . . , n.
In the conventional development and mass production of semiconductor devices of multiple types, devices of each type being manufactured in a small number, the devices of each type are subjected to an acceleration test to thereby estimate their failure ratio on the market and carry out appropriate initial-failure screening. Accordingly, a lot of time and effort are required for the development, and it is difficult to optimize the initial-failure screening in the mass production stage. This makes it difficult to obtain reliable products in a stable manner. Under these circumstances, it is demanded to reduce the time and effort required for the development, and to construct a system for optimizing the initial-failure screening conditions for dealing with an increase or decrease in the failure ratio on the market after the mass production stage, thereby providing highly reliable products.